# On Event

Raise an event in the event bus.

```sig
control.onEvent(control.eventSourceId(EventBusSource.MICROBIT_ID_BUTTON_A), control.eventValueId(EventBusValue.MICROBIT_EVT_ANY), () => { });
```

**This is an advanced API.**  For more information, see the
[@boardname@ runtime messageBus documentation](https://lancaster-university.github.io/microbit-docs/ubit/messageBus/).